ISC (Science) ISC Class 12 - CISCE Question Bank Solutions for Physics (Theory)

Represent diagrammatically how the incident planar wavefronts of wavelength λ pass through an aperture of size d, when d is approximately equal to λ.

During Rutherford’s gold foil experiment, it was observed that most of the α-particles did not deflect. However, some showed a deflection of 180°. 

What hypothesis was made to justify the deflection of α-particle by 180°?

Represent diagrammatically how the incident planar wavefronts of wavelength λ pass through an aperture of size d, when d is approximately equal to λ.

In Bohr’s model of the hydrogen atom, the radius of the first orbit of an electron is r₀ . Then, the radius of the third orbit is:

a) `r_0/9`

b) `r_0`

c) `3r_0`

d) `9r_0`

What is the ratio of the speed of gamma rays to that of radio waves in a vacuum?

Draw separate energy band diagram for conductors, semiconductors and insulators and
label each of them.

A fish which is at a depth of l2 em .in water `(mu = 4/3)` is viewed by an observer on the bank of a lake. Its apparent depth as observed: by the observer is:

a) 3 cm

b) 9 cm

c) 12 cm

d) 16 cm

if `E_p` and `E_k` represent potential energy and kinetic energy respectively, of an orbital electron, then, according to B9hr's theory:

a)`E_k = -E_p"/"2`

b) `E_k = -E_p`

c) `E_k = -2E_p`

d) `E_k = 2E_p`

How are electric vector `(vec "E")`, magnetic vector `(vec "B")` and velocity vector `(vec "C")` oriented in an electromagnetic wave?

Whatis the difference between analogue signal and. digital signal?

On the basis of Huygens Wave theory of light, show that angle of reflection is equal to the angle of incidence. You must draw a labelled diagram for this derivation

In an experiment of the photoelectric effect, the graph of maximum kinetic energy E_K of the emitted photoelectrons versus the frequency v of the incident light is a straight line AB shown in Figure 6 below:

Find:

1) Threshold frequency of the metal

2) The work function of the metal.

3) Stopping potential for the photoelectrons emitted by the light of frequency `v = 30 xx 10^14 Hz`

On the basis of Bohr's theory, derive an expression for the radius of the n^th orbit of an electron of the hydrogen atom.

The energy associated with light of which of the following colours is minimum : 

This is an example of step-up transformer.

Define frequency modulation and state any one advantage of frequency modulation (FM) over amplitude modulation (AM). 

State any two Bohr’s postulates and write the energy value of the ground state of the hydrogen atom. 

In which of the following systems will the wavelength corresponding to n = 2 to n = 1 be minimum?

Calculate the momentum of a photon of energy 6 x I 0^-19 J. 

According to Bohr, 'Angular momentum of an orbiting electron is quantized'. What is meant by this statement?